FreezeIt Background App Optimizer

Overview

FreezeIt Background App Optimizer (authored by JARK006) is a high-performance systemless battery optimization daemon designed to solve modern Android standby battery drain.

Modern mobile applications often spawn numerous background services, push monitors, analytics daemons, and tracking loops that keep the CPU in active awake states (wakelocks). Standard Android Doze helps, but is often bypassed by apps registering high-priority job schedulers. FreezeIt addresses this at the kernel level by placing non-essential processes into the Linux freezer cgroup.

Technical Architecture & How It Works

FreezeIt utilizes the Linux control group (cgroups) freezer subsystem (CONFIG_CGROUP_FREEZER):

1. Process State Management

When an application moves out of the foreground:

Foreground Activity -> App Minimized -> Grace Period (e.g. 30s) -> Kernel Freeze

The daemon writes the application’s process IDs (PIDs) into the cgroup freezer control file:

echo $PID > /sys/fs/cgroup/freezer/freezeit/cgroup.procs
echo "FROZEN" > /sys/fs/cgroup/freezer/freezeit/freezer.state

In the FROZEN state:

• The Linux kernel scheduler skips all threads belonging to the task.
• Zero CPU instructions are executed.
• Memory remains locked in RAM, preventing cold-launch disk I/O when the user returns.

2. Resumption & Focus Handshake

When the user switches back to the application or a high-priority system broadcast arrives:

echo "THAWED" > /sys/fs/cgroup/freezer/freezeit/freezer.state

The threads resume execution immediately at their exact previous CPU instruction pointer with zero delay.

Configuration & Whitelist Management

Customize behavior via the local configuration files:

# Whitelist path
/data/adb/modules/freezeit/whitelist.txt

Add application package names (one per line) to keep them running continuously:

com.whatsapp
org.telegram.messenger
com.google.android.gms